A common practice in the care of immobilized, bedridden patients is the rotation of a patient on his side and the propping of him in that position with pillows. The patient is periodically moved between a neutral or flat position and rolled positions to both his right and left side. Such care reduces the tendency for fluid accumulation in a single spot in the lungs. It also has skin care benefits in reducing the tendency to pressure sores.
The effecting of such movements automatically has been proposed in conjunction with air support beds for patients at high risk from pressure sores. PTO application WO 88/09651, published Dec. 15, 1988, illustrates an air support bed available commercially from Kinetic Concepts, Inc. which incorporates a series of odd shaped air pillows in an air support bed to serve both the basic function of reduced pressure air support and automatic adjustment of the patient's rotational orientation. A simpler system for effecting rolling in conjunction with an air support bed is illustrated in my U.S. Pat. No. 4,953,247.
It has also been proposed to provide automatic rolling overlays in conjunction with conventional mattresses. U.S. Pat. Nos. 3,477,071, 3,775,781, 3,415,240, and 4,941,221, as well as U.K. Patent 2,026,315 and German Patent 2816642, are examples of such overlay systems which have been proposed for use atop conventional bed mattresses. Despite these latter proposals, the utilization of air operated overlays in conjunction with conventional mattresses has not become a wide spread practice. It is believed in part that the problems of such overlays when used with conventional mattresses include the fact that the patient is subject to feelings of insecurity in the angled position, as well as the fact that the patient may effectively be "wedged" up into the angled position, producing shear on the shoulder. Moreover, the patient may, in part, be slid from side to side on the bed rather than merely being rotated in place.
Accordingly, despite the considerable attention which has been directed to the air operation of patient rotational orientation systems, there remains a need for a simple system which can be used both on top of conventional mattresses and air support beds which will effectively produce the desired automatic adjustment of the patient's rotational orientation in a comfortable and stable manner with minimum shear, while not creating patient anxiety. It is believed that the overlay system of this invention represents a substantial advance over the state of this art.